Anti-Surge Driving Strategy Based on the Thyristor-Controlled Phase-Shifting Transformer

The Thyristor-Controlled Phase Shifting Transformer (TCPST) holds significant prospects in the increasingly complex power grid flow control due to its reliable load regulation and cost-effectiveness. However, the semi-controlled characteristics of thyristors introduce the possibility of current surges of short-circuit during mode switching, restricting the widespread engineering application of TCPST. To address this issue, this paper proposes an anti-surge driving strategy for mode switching on the basis of the TCPST: a locking driving strategy that combines current direction of valve-group and operating mode to address the current surge issues induced by coil short-circuit during mode switching. Additionally, an RC buffer circuit is added within the valve-group, and a power reference threshold is introduced in the driving strategy to reduce the voltage surge associated valve-group momentary open-circuit. Finally, simulations are conducted on a 220kV grid environment with the TCPST, confirming the effectiveness of the proposed anti-surge driving strategy.